Respected Sir/madam,

am a beginner in learning Hibernate . starting with the version 3.1.2
using the distribution reference manual as my primary source of information.In the introduction chapter (pdf). page number 13

<set name="emailAddresses" table="PERSON_EMAIL_ADDR">
<key column="PERSON_ID"/>
<element type="string" column="EMAIL_ADDR"/>
</set>

when executed EntityManager class at the database side for the table
PERSON_EMAIL_ADDR only the PERSON_ID is made to primary key and refers(foreign key) to the PERSON TABLE'S PERSON_ID primary key.

another column EMAIL_ADDR is not made to a primary key . But the material says in the next page 14 along with diagram that both the columns act as composite key.

please tell me where i have gone wrong.looking forward for the reply.

Hello, I'm not familiar with the example you're talking about but it sounds like there is a little confusion as to what is what.

I don't think the PERSON_ID is the primary key in the PERSON_EMAIL_ADDR table. The meaning of the properties in the set I think mean something like this:

table="PERSON_EMAIL_ADDR" - In order to get the data from this set, we look at the PERSON_EMAIL_ADDR table
key column="PERSON_ID" - The column PERSON_EMAIL_ADDR.PERSON_ID matches the primary key of the entity we're mapping. This tells us what email address belongs to who
column="EMAIL_ADDR" - Use the values in PERSON_EMAIL_ADDR.EMAIL_ADDR to populate the set.

Because this isn't a one to one relationship, a the email table can't create a primary key on a non-unique column (person_id) it uses the combination of the two to create a PK. Not really sure why it doesn't just have its own PK though. Hope that helps.

please kindly click on the link provided

http://sourceforge.net/project/showfile ... _id=127784

download the version 3.1.2 .zip file , when extracted

{..}\hibernate-3.1.2\hibernate-3.1\doc\reference\en\pdf\hibernate_reference.pdf

this is the manual am following . please i would be very much thankful if u give a glance to the pages 13,14 which refers to my query.

looking forward for ur reply.